$ npm install ngx-monaco-editor@9 --save

Add below to assets in angular.json:

{
    "glob": "**/*",
    "input": "node_modules/ngx-monaco-editor/assets/monaco",
    "output": "./assets/monaco/"
}

app.module.ts:

import { MonacoEditorModule, NgxMonacoEditorConfig } from 'ngx-monaco-editor';

const defaultEditorConfig: NgxMonacoEditorConfig = {
  defaultOptions: {
    theme: 'vs-dark',
    automaticLayout: true,
    minimap: {
      enabled: false
    },
    scrollBeyondLastLine: false,
    scrollbar: {
      vertical: "hidden",
      horizontal: "hidden"
    }
  }
};

Add below to imports:

MonacoEditorModule.forRoot(defaultEditorConfig)

Typescript:

editorOptions = { language: 'python' };

Template:

<ngx-monaco-editor [options]="editorOptions" [(ngModel)]="html"></ngx-monaco-editor>